Phthalazinones preparation

Azelastine (107) is an antiallergic/antiasthmatic agent prepared from 4-chlorobenzyl-2 -car-boxyphenylketCHie (105) by condensation with hydrazine to give the phthalazinone (106) followed by reaction of the sodium salt of this last with 2-(2-chloroethyl)-N-methylpyrrolidine (presumably involving nucleophilic ring expansion of the bicyclic quaternary salt putatively formed as a first product) to complete the synthesis [30]. 

The reaction of azines 107, prepared in situ from aldehydes or ketones and hydrazine, afforded the Ugi adducts 108. The acid treatment of 108 resulted in the hydrolytic cleavage of the imino group with formation of the hydrazides, which immediately cyclized to phthalazinone amides 109 (Scheme 2.39) [70]. 

Quinolyl)pyrazoIo[3,4-i7]pyridazincs were prepared by cyclocondensation reactions of an anilino-pyrazole acid with acetaldehyde <02JHC869>. Cyclopentadienyl-derived y-diketones and arylhydrazines condensed to 4-(l,4-diaryl-2//-cyclopent[d]pyridazin-2-yl)-benzenesulfonamides <02H(57)2383>. Sulfonated polyfphthalazinone ether sulfone)s 37 were prepared by polycondensation of 4-(4-hydroxyphenyl)phthalazinone 36 with various ratios of disodium 5,5 -sulfonylbis(2-fluorobenzenesulfonate) and bis(4-fluorophenyl)sulfone <02P5335>. 

The fact that the polarographic data for 1 at pH 5 suggests a two-electron reaction, whereas the preparative results prove a four-electron reduction, means that a slow chemical step occurs after the uptake of two electrons. The partly reduced molecule diffuses from the microelectrode before the chemical follow-up reaction has occurred, but this does not matter in an exhaustive, preparative reaction. The rate of the slow step is pH-dependent and this step is not apparent at low pH where it is sufficiently fast. The slow step is suggested to be the acid-catalyzed dehydration of 2 to the quaternary phthalazinone (5). 

Phenyl- and 6-trifhioromethyl-l,4-dichlorophthalazine have also been prepared in good yield (43% and 84%, respectively) from the corresponding 6-substituted, 4-hydroxy-l-(2H)phthalazinones.117 118 Similarly, 1,4-dibromophthalazine was prepared by heating 4-hydroxy-l-(2H)phthalazinone with phosphorus pentabromide in 78-97% yield.115,11 However, treating 4-hydroxy-l-(2H)phtha-lazinone (48) with phosphorus oxybromide gives 1-bromophthalazine only (88% yield).115 116... 

Su et al. [138] prepared composite PEMs from sulfonated poly(phthalazinone ether ketone) (sPPEK) and various amounts of sulfonated silica nanoparticles (silica-SO3H). The use of silica-SO H was seen to compensate for the reduction in the lEC of the membrane, while the strong -SO3H/-SO3H interaction between sPPEK chains and silica-SO3H particles led to ionic crosslinking in the membrane structure, which improved not only the thermal stability but also the methanol resistance. 

Most such compounds have been made by primary synthesis (see Chapter 8), by ozonolysis of alkenylphthalazines (see Section 9.2.2), or by alkylation or acylation of tautomeric phthalazinones (see Section 11.1.2.1). Minor preparative routes are... 

The majority of polymer membranes used for microfiltration and ultrafiltration of liquids are prepared by the wet phase inversion process. Such membranes exhibit a typical asymmetric structure characterized by a thin dense surface layer and a thick microporous bulk. Poly(phthalazinone ether sulfone ketone) (PPESK) copolymers, c.f. Figure 7.10, show glass transition temperatures in the range of 263-305°C. The polymers show an outstanding chemical stability. They are soluble only in 98% H2SO4. Concentrated aqueous solutions of sodium chlorate, hydrogen peroxide, acetic acid, and nitric acid show no effect. ... 

B. Zhang, T. Wang, S. Zhang, J. Qiu, and X. Jian. Preparation and characterization of carbon membranes made from poly(phthalazinone ether sulfone ketone). Carbon, 44(13) 2764-2769, November 2006. 

Y. Su, X. Jian, S. Zhang, and G. Wang. Preparation and characterization of quatemized poly(phthalazinone ether sulfone ketone) NF membranes. J. Membr. ScL, 241(2) 225-233, October 2004. 

Sulfonated poly(phthalazinone ether ketone nitrile) (SPPEKN) copolymers prepared by the copolymerization of disodium 3,3 -disulfonate-4,4 -difluorobenzophenone, 2,6-difluorobenzonitrile, and 4-(4-hydroxy-phenyl)-l(2H)-phthalazinone exhibit a tensile strength higher than that of Nafion 117. The proton conductivities of the acid form of SPPEKN copolymers, with a feed ratio or sulfonated to unsulfonated monomer above 0.35, are around lO Scm at 80°C, which is close to that of Nafion 117.39... 

Sulfonated poly(phthalazinone ether sulfones) were directly prepared by polycondensation of 4-(4-hydroxyphenyl)phthalazinone with various rations of disodium salt of 5,5 -sulfonylbis-(2-fluorobenzenesulfonate) to 4-lluorophenylsulfone [117]. 

A suitable polymer material for preparation of carbon membranes should not cause pore holes or any defects after the carbonization. Up to now, various precursor materials such as polyimide, polyacrylonitrile (PAN), poly(phthalazinone ether sulfone ketone) and poly(phenylene oxide) have been used for the fabrication of carbon molecular sieve membranes. Likewise, aromatic polyimide and its derivatives have been extensively used as precursor for carbon membranes due to their rigid structure and high carbon yields. The membrane morphology of polyimide could be well maintained during the high temperature carbonization process. A commercially available and cheap polymeric material is cellulose acetate (CA, MW 100 000, DS = 2.45) this was also used as the precursor material for preparation of carbon membranes by He et al They reported that cellulose acetate can be easily dissolved in many solvents to form the dope solution for spinning the hollow fibers, and the hollow fiber carbon membranes prepared showed good separation performances. 

Kim DS, Shin KH, Park HB, Lee YM (2004) Preparation and characterization of sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK)/silica hybrid membranes for direct methanol fuel cell applications. Macromol Res 12 413-421... 

The use of a phthalazinone monomer results in a melt processable semi-crystalline PEEK with a glass transition temperature above 180 °C [14]. This polymer type is not soluble in organic solvents such as chloroform. The polymer can be prepared by the polymerization of 4,4 -difluorobenzophenone with 4,4 -biphenol and 4-(4-hydroxyphenyl)phthalazin-l(2H)-one (phthalazinone). These polymers can be processed via melt processing such as extrusion and injection molding. 

Nafion (Fu et al. 2008). However, the corresponding proton conductivity value is lower. The methanol crossover, however, is only one-third of that found in Nafion 115, compared at the same thickness. Although the PSf membrane has lower proton conductivity than Nafion, the lower production cost and methanol crossover make it a promising alternative for DMFC. Sulfonated poly(phthalazinone ether ketone) (SPPEK) has been discovered as a new kind of PEM for DMFC due to its superior performance in terms of chemical and oxidative resistances, mechanical strength, and thermal stability (Gao et al. 2003). Tian et al. reported that SPPEK prepared from direct polymerization of presulfonated monomer has better performance than that of postsulfonation (Tian et al. 2005). Unfortunately, with direct polymerization it was hard to control the DS and location of sulfonation. 

Tian, S.H., Shua, D., Chen, Y.L., Xiao, M. and Meng, Y.Z. 2005. Preparation and properties of novel sulfonated poly(phthalazinone ether ketone) based PEM for PEM fuel cell application. J. Power Sour. 158 88-93. 

Proton exchange membranes (PEM) were also prepared by solution blending of sulfonated poly(phthalazinone ether ketone) (sPPEK) and various amotmts of sulfonated silica nanoparticles (silica-SOsH) [58]. The solution blending techiuque was also used in combination with compression molding thus, poly(ether ether ketone) (PEEK)-based nanohybrids were fabricated by means of compression molding at 400°C under a pressure of 60 MPa using silica surface-modified with stearic acid and PEEK [59]. 

Song et al. [72] synthesized fluorinated poly(phthalazinone ether)s (FPPEs) via a modified nucleophilic aromatic substitution using mild reaction conditions. Potassium fluoride and calcium hydride were used as the catalyst and base in preparing highly... 

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